President Barack Obama presents the Presidential Medal of Freedom to Stephen Hawking, the physicist and author, at the White House in Washington, Aug. 11, 2009. Hawking, the Cambridge University physicist and best-selling author who roamed the cosmos from a wheelchair, pondering the nature of gravity and the origin of the universe and becoming an emblem of human determination and curiosity, died at his home in Cambridge, England, on March 14, 2018. He was 76.

A family spokesman announced the death in a statement to several news media outlets.

“Not since Albert Einstein has a scientist so captured the public imagination and endeared himself to tens of millions of people around the world,” Michio Kaku, a professor of theoretical physics at the City University of New York, said in an interview.

Hawking did that largely through his book “A Brief History of Time: From the Big Bang to Black Holes,” published in 1988. It has sold more than 10 million copies and inspired a documentary film by Errol Morris. The 2014 film about his life, “The Theory of Everything,” was nominated for several Academy Awards, and Eddie Redmayne, who played Hawking, won the best-actor Oscar.

Scientifically, Hawking will be best remembered for a discovery so strange that it might be expressed in the form of a Zen koan: When is a black hole not black? When it explodes.

What is equally amazing is that he had a career at all. As a graduate student in 1963, he learned he had amyotrophic lateral sclerosis, a neuromuscular wasting disease also known as Lou Gehrig’s disease. He was given only a few years to live.

The disease reduced his bodily control to the flexing of a finger and voluntary eye movements but left his mental faculties untouched.

He went on to become his generation’s leader in exploring gravity and the properties of black holes, the bottomless gravitational pits so deep and dense that not even light can escape them.